Technical Field
The present disclosure relates to methods of fabricating transition metal dichalcogenides. More particularly, the present disclosure relates to methods of fabricating transition metal dichalcogenides at low temperature.
Description of Related Art
In recent years, two-dimensional material such as graphene, has become the most popular scientific research topic in the material science because of its excellent electrical properties, optical properties and physical characteristics. Moreover, its high energy efficiency is very useful for various applications such as fuel cells, solar batteries, flexible displays, capacitors, sensors, etc.
However, graphene is a material that has zero band gap in its native state, thus it is difficult to integrate graphene with current silicon process. In contrast, transition metal dichalcogenides (TMDs) has a band gap between the conduction and valence band, so that TMDs has become a new direction of scientific research.
TMDs are layered materials with strong in-plane bonding and weak out-of-plane interactions similar to graphite. Although the physical properties bulk TMDs have been studied for decades, recent studies have predicted exceptional physical properties upon reduced dimensionality attracting lots of attention due to the versatile chemistry displayed in 2D. Properties such as a direct bandgap with high mobility when TMDs reach nanometer scale thickness, making TMDs very attractive for low power and high speed electronics, optoelectronics, light emission, and sensors between others. Nevertheless, the lack of a large area and reliable synthesis method that can be combined with the actual manufacturing process for electronic devices is a major drawback for the development of this technology.
Conventionally, a peeling method such as exfoliation and a chemical vapor deposition (CVD) method are usually used for fabricating TMDs. Although the peeling method is simple and can generate high-quality two-dimensional material, the number of the film layer is difficult to control, and it is very difficult to apply in large scale production. In addition, the CVD method need high temperature over 500° C. under degree of vacuum of more than 760 Torr for fabricating TMDs, and Hydrogen sulfide, H2S, is a toxic gas that is usually used as the fabricating source in the CVD method.